Table 1 Characteristics of the study population
Asthma cases (N = 608) | Non-asthma controls (N = 839) | |
|---|---|---|
Age (y), mean (SD) | 6.1 (2.0) | 6.6 (2.1) |
BMI, median (IQR) | 15.8 (2.9) | 15.7 (3.4) |
Birthweight, mean (SD) | 3309 (489) | 3276 (507) |
Gestational weeks at birth, median (IQR) | 39 (2) | 39 (1) |
Maternal age at birth (y), mean (SD) | 28.6 (3.5) | 27.9 (3.9) |
Maternal educational level, (n, %) | ||
≤ 9 years | 40 (6.6) | 138 (16.4) |
10–12 years | 79 (13) | 151 (18) |
13–16 years | 395 (65) | 443 (52.8) |
> 16 years | 49 (8.1) | 45 (5.4) |
Paternal educational level, (n, %) | ||
≤ 9 years | 38 (6.2) | 125 (14.9) |
10–12 years | 74 (12.2) | 153 (18.2) |
13–16 years | 383 (63) | 437 (52.1) |
> 16 years | 68 (11.2) | 66 (7.9) |
Gender, (n, %) | ||
Boy | 368 (60.5) | 454 (54.1) |
Girl | 240 (39.5) | 385 (45.9) |
Family history of allergy, (n, %) | ||
No | 275 (45.2) | 627 (74.7) |
Yes | 314 (51.6) | 194 (23.1) |
Delivery mode, (n, %) | ||
Vaginal | 211 (34.7) | 328 (39.1) |
Caesarean section | 394 (64.8) | 507 (60.4) |
Exclusive breastfeeding, (n, %) | ||
< 6 months | 301 (49.5) | 426 (50.8) |
≥ 6 months | 305 (50.2) | 413 (49.2) |
Carpet in the dwelling, (n, %) | ||
No | 562 (92.4) | 786 (93.7) |
Yes | 37 (6.1) | 41 (4.9) |
Pet in the dwelling, (n, %) | ||
No | 539 (88.7) | 740 (88.2) |
Yes | 58 (9.5) | 94 (11.2) |
ETS at birth, (n, %) | ||
No | 430 (70.7) | 547 (65.2) |
Yes | 172 (28.3) | 289 (34.4) |
ETS at present, (n, %) | ||
No | 421 (69.2) | 521 (62.1) |
Yes | 178 (29.3) | 312 (37.2) |
Visible mold in the dwelling, (n, %) | ||
No | 457 (75.2) | 720 (85.8) |
Yes | 151 (24.8) | 119 (14.2) |